return to C index

return to index page

PTD - 189

Test Directory - Caffeine


Clinical Indications

Caffeine is used in neonates as a CNS stimulant to treat apnoea of prematurity. It is used in preference to theophylline since dose regimes are simpler, effects more predictable and toxicity is less of a problem. 
The reduced toxicity of caffeine and more predictable effects combine to reduce the need for therapeutic monitoring and a satisfactory clinical response can usually be obtained on standard dose regimes without the need for monitoring

Request Form

Combined Pathology Blood form (Yellow/Black)


Referred test: Analysed by Guy's and St Thomas' Hospital if specific criteria met.

Specific Criteria

Monitoring is rarely useful but may be valuable if response is inadequate despite apparently adequate dosing or if unexpected toxicity develops. Symptoms of toxicity in neonates include jitteriness and gastrointestinal disturbance.

Patient Preparation

Samples should preferably be collected pre-dose.

Turnaround Time

Up to 1 week.




1 ml


Paediatric orange top (lithium-heparin)
Yellow top (SST) tubes must not be used.

Causes for Rejection

Not meeting specific criteria for analysis.

Reference Range and Interpretation

Target Range: 50 - 150 umol/L
In neonates with apnoea, pharmacological activity begins at plasma concentrations of 15 - 20 umol/L and concentrations in the range 25 - 100 umol/L are generally associated with improved respiration.

Unit Conversion

To convert from mg/L to umol/L multiply by 5.15

Lab. Handling

Processing: Aliquot (MPA) and store at 4C in separating fridge (CB39). Referral:  CAF and send or BPRO and save in separating freezer (CB40) at -20C, saved frozen rack. Send as soon as possible.

Version 1.0 / April 2014                                                                                                          Approved by: Consultant Biochemist